def. go with the xeon dual....or if you wanna get real dreamy, check out the new dell server line they have QUAD Xeons (xeon 4 ghz x 4) and get upto 12 ghz in processor speed.
Be sure to add in all the 500 gig hard drives (SATA RAID 0) so if you load 16 of them into that Dell box it becames 8 Terabytes of storage. Did I also mention they were hot swapable (therefore you can order an additional 16 hot swaped 500 gig drives and bring your total storage to 16 Terabytes when you swap out the drives!)
Now include the 70" Panasonic LCD TV/COMP Display for your monitor (of coarse its got a computer port on it built in) with the highest grade graphics card......and your done.
Good Luck
Jim